Electrostatic Chuck Gap Layout for SiC Wafer Stress Relief
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Solution Overview
Problem
During ion implantation processing, silicon carbide wafers experience thermal stress and cracking due to restricted expansion caused by the electrostatic chuck, and subsequent jumping during separation, as existing wafer supporting devices cannot effectively manage thermal stress and heat distribution.
Innovation Solution
A wafer supporting device with a support base having a heater and an electrostatic chuck positioned at different perpendicular distances, creating a gap to reduce thermal stress and prevent cracking, and allowing for controlled heat transfer through gas supply passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electrostatic chuck attracts the entire back surface of the wafer for stable positioning, then the wafer positioning stability is improved, but thermal stress increases and causes cracking during high-temperature processing
Solution Approach 1:
The electrostatic chuck is divided into multiple independent electrode regions (first electrostatic chuck and second electrostatic chuck) that can be independently controlled. This segmentation allows only the necessary portion of the wafer to be attracted, reducing thermal stress while maintaining sufficient positioning stability during high-temperature processing
Solution Approach 2:
Different regions of the electrostatic chuck have different attraction characteristics - the first electrostatic chuck provides strong attraction for stable positioning, while the second electrostatic chuck provides weaker attraction to reduce thermal stress. This local differentiation optimizes both stability and stress reduction
2Reliability
If the electrostatic chuck holds the wafer firmly for processing, then the processing reliability is improved, but the wafer jumps during separation from the chuck
Solution Approach 1:
The electrostatic attraction force is made dynamically adjustable by independently controlling the first and second electrostatic chucks. During processing, strong attraction ensures reliability; during separation, the attraction can be reduced or selectively applied to prevent wafer jumping
Solution Approach 2:
By segmenting the electrostatic chuck into independently controllable regions, the attraction force can be selectively applied or released during separation, preventing sudden wafer jumping while maintaining processing reliability
3Temperature
If the heater raises the wafer temperature to high levels for ion implantation annealing, then the annealing effectiveness is improved, but thermal stress and cracking increase
Solution Approach 1:
The heating and electrostatic attraction are applied to different regions - the heater raises the overall wafer temperature for effective annealing, while the electrostatic chuck selectively attracts only specific areas, allowing thermal expansion in non-attracted regions to reduce thermal stress while maintaining necessary temperature for processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces thermal stress, suppresses wafer cracking during processing, and prevents jumping during separation by minimizing the area fixed by the electrostatic chuck and allowing controlled heat management.
Implementation Method 1
The raising of the wafer temperature is performed using a heater unit built in a wafer supporting device
Implementation Method 2
an electrostatic chuck supported by the support base, the electrostatic chuck having an attraction surface configured to attract a wafer
Data Source
AI summary
A wafer support device includes a support base having a wafer-facing surface, the support base comprising a heater, and an electrostatic chuck supported by the support base, the electrostatic chuck having an attraction surface configured to attract a wafer for wafer processing. During the wafer processing, the wafer-facing surface and the attraction surface are positioned at respective different positions in a direction perpendicular to the wafer-facing surface so that the attraction surface is separated from the wafer-facing surface by a distance.